Apparatus for forming water gel

ABSTRACT

A portable fire extinguisher contains a supply of water and a gel forming chemical to be expelled under pressure through a mixing device contained in a small space by arranging a channel to follow a tortuous course, with an inlet for water and chemical at one end of the channel and further inlets for water at successive locations along the channel.

[ Dec. 10, 1974 United States Patent Lindgren et a1. v A

XX 64 39 l/ ,2 22 22 2 15 APPARATUS FOR FORMING WATER GEL 3,325,056 6/1967 3,423,073 1/1969 3,642,072 2/1972 3,645,337 2/1972 Arge..............

Livingston L1v1ngston [75] Inventors: Mats Lindgren, Stockholm; Hillar Malm, Sundbyberg, both of Sweden Incentive Research & Development AB (1RD), Stockholm, Sweden Aug. 30, 1973 [73] Assignee:

Primary Examiner-M. Henson Wood, Jr. Assistant Examiner--Michael Mar [22] Filed:

[21] Appl. No.: 393,080

ABSTRACT Foreign Application Priority Data Sept. 6', 1972 Sweden........1.................... 11513/72 [52] U5, A portable fire extinguishercontains a supply of water 239/318 and a gel forming chemical to be expelled under pres- A62c 37/06 169/9, 14, 15, 169/32, .37, 44, 85; 222/1292, 136, 399; 239/318 sure through a mixing device contained in a small [51] Int.

30 31 R space by arranging a channel to follow a tortuous course, with an inlet for water and chemical at one end of the channel and further inlets for water at successive locations along the channel.

[58] Field of Search [56] References Cited UNITED STATES PATENTS 2,988,151 6/1961 Dion-Biro................,......,..... 169/14 12 Claims, 11 Drawing Figures PATENHL i531 1 74 SHEET 2 UF 5 FIG.2

PAIENIE 1c 1 0 I974 FIGH APPARATUS FOR FORMING WATER GEL The present invention refers to an apparatus for continuous forming of water gel, especially for fire fighting purposes, bymixing water and a liquid gel former.

Water gel has proved to be considerably more efficient than water for fire fighting purposes. One reason for this is that a gel could be fastened on a surface, e.g. a vertically wall in thick layers, whereas a watershed only gives rise to a very thin waterfilm. This means that a gel layer has a considerably better cooling effect and also a better smothering effect on fire than a waterfilm and furthermore the effect of a gel spraying will be maintained for a much longer time than the effect of a water spraying. A water gel for fire fighting purposes is e.g. described in the Swedish Pat. No. 310,312. This water gel consists of water with an addition of 0.1 percent of an organic gel former which is composed by a surface active polyethylene oxide derivative and a volatile hydrocarbon oil, the mixing ratio being such that the formed water gel has a consistency suitable for fire fightingpurposes.

The forming of such a water gel by mixing water and gel former does however involve considerable difficulties, especially if the gel formation should take place continuously at the speed by which the formed water gel is sprayed out at fire fighting. The Swedish Pat. No. 317,875 describes an apparatus for the continuous forming of water gel for fire fighting through continuous mixing of water and gel former. This mixing device is composed by a number of tubes which are connected in series via intermediate mixing or whirling chambers, the first tube in the series being supplied with gel former and water and each of the subsequent tubes being supplied by water and the water gel from the previous tube in the series of tubes. This apparatus does however suffer from the drawback that it has a very complicated design and is thus rather costly to manufacture and will furthermore be very space demanding. It is thus not very suitable for mobile fire extinguishers such as handextinguishers.

The Swedish Pat. application Ser. No. 12466/70 describes another apparatus for continuous forming of a water gel by mixing water and a gel former where a long flexible tubing which serves the purpose of transporting the gel from the fire extinguisher to the fire also serves the purpose of being a mixing chamber for the gel and thus at one end is supplied with water and gel former in such proportions that a fully developed gel is obtained close to the opposite end of the tubing. This mixing chamber could however only be used when the water gel is to be transported to the fire via a long flexible tubing, e.g. a conventional fire hose but could not be used in such fire extinguishers, e.g. hand fire extinguishers which are not provided with long flexible tubings but are intended to be brought close to the fire.

It is an object of the present invention to provide an improved apparatus for continuous forming of water gel, especially for fire fighting purposes by mixing water and a liquid gel former, the apparatus having a simple design, so that it could be made in large quantities at low cost and having small dimensions so that it could be used in small portable fire extinguishers e.g. hand fire extinguishers not requiring a long flexible tubing for mixing the water and the gel former.

The characteristics of the invention will appear from the enclosed claims.

The invention will now be described in detail, reference being made to the enclosed drawing which shows a number of embodiments of the invention and in which:

FIG. 1 shows an axial cross section through a hand fire extinguisher provided with a first embodiment of a gel former according to the invention;

FIGS. 2-5 show radial cross sections on an enlarged scale through the mixing unit of the fire extinguisher according to FIG. 1, this cross section being cut along the lines Il-II, IIIIII, IV-lV, and V-V respectively of FIG. 1;

FIGS. 6-8 show axial cross sections through one part of the mixing unit, the cross sections being out along the lines VI-VI, VIIVII and VIII-VIII respectively of FIG. 5;

FIG. 9 shows the envelop surface of the central cylindrical body of the mixing unit included in the fire extinguisher of FIG. 1;

FIG. 10 is a schematic perspective view of another embodiment of a mixing unit according to the invention which e.g. could be used in the fire extinguisher of FIG. 1; and

Hg. 11 is a schematic perspective view of another possible embodiment of a mixing unit according to the invention.

The fire extinguisher shown in FIG. 1 consists of an external gas proof tank or container 1 which is intended to be filled up with water. At its upper end the container 1 is provided with a supply tube 2 the outer end of which is closed by means of a gas tight cover 3. This cover holds a pressure gas container 4 which could be opened from the outside of the cover 3 so as to make the'gas under pressure in the container 4 flow out into the water tank 11 and give rise to an over pressure within the tank, which pressure is sufficient to force the water out from the tank 1 as will be described below. The tank 1 is further provided with a tubular container 5 which contains the liquid gel former. This container 5 is at its upper end by means of a clamp ring 6 attached to a short tubular socket 7 which is welded to a bore in the upper end of the container 1. In the upper end of the gel former container 5 the gel mixer denoted 8 is mounted.

As appears from FIG. 1 and more in detail from FIGS. 2-9 the gel mixer essentially consists of a central cylindrical body 9 which is closely surrounded by a tubular socket 10. As appears from FIG. 9, which shows the envelop surface of the cylindrical body 9, and where the degree indications correspond to the degrees shown in FIG. 4, the cylindrical body 9 has an envelop surface provided with a meandering, or zigzag, groove 11 which in combination with the surrounding socket 10 forms a channel constituting a flow and mixing channel for the water gel. The flow direction through the channel 11 is indicated by the arrows. This flow and mixing channel 11 is at its upstream end provided with two inlet ports 12 and 13. The port 12 is intended to be used for supply of gel former and is via an inner channel 14 (FIG. 5) within the body 9 connected to an ascending tube 15 connected to the bottom end of the body 9, the tube 15 running through the gel former container 5 to the bottom of the container, so that the gel former within the container 5 can be forced up through the tube 15 into the mixing channel 11 through the inlet port 12. The other inlet port 13 at the upstream end of the channel 11 is intended for the supply of water and is by means of an internal channel 16 .within the body 9 connected to a tube 17 which runs from the body 9 through the complete gel former tank out into the surrounding water tank 1 close to its bottom. As pressure is generated within the tank 1, when the pressure gas container 4 is opened, this pressure could thus force water from the water tank through the tube 17 and through the channel 16 into the body 9 and into the channel 11 through the inlet port 13.

The water flowing through the inlet port 13 and the gel former flowing through the inlet port 12 are mixed within the first part of the flow and mixing channel 11 to a water gel having a relatively high concentration of gel former, this water gel being mixed up with more water within the subsequent part of the mixing channel 11. This is achieved by providing the channel 11 with a number of further inlet ports 18, 19, 20, and 21 arranged along the channel. These water inlet ports 18-21 in the mixing channel 11 are connected via inner channels 22, 23, 24 and 25 respectively within the body 9 to a further tube 26 connected to the lower end of the body 9, the tube 26 being arranged concentrically round the tube 17 and running parallel to this tube through the gel former tank to the water tank 1 close to its bottom.

The lower ends of the water tubes 17 and 26 are suitably arranged at such distance from each other that the water flows in the separate tubes do not affect each other. The reason for having separate water supplies to the inlet port 13 and the further inlet ports 18-21 is that the big total water flow through the inlet ports 18-21 otherwise will have a tendency to give rise to a sub pressure at the water inlet port 13 which would imply that no water would be supplied into the mixing channel 11 through this inlet port 13 but instead gel former suplied through the inlet port 12 would be drawn out through the port 13.

By the supply of further water to the mixing channel through the water inlet ports 18-21 the water gel in the mixing channel 11 will be provided with an increasing amount of water so that at the end of themixing channel ll'a water gel having the desired composition and consistency will be' at hand.

Immediately before the first further water inlet port 18, the mixing channel 11 is suitably provided with a constriction 27 through which the water gel mixed up in the first part of the channel 11 is drawn by means of the ejector effect from the water flowing through the inlet port 18. By means of suitably dimensioning the construction 27 and the water inlet port 18 it is possible to adjust the mixing ratio between the water gel formed within the first part of the mixing channel 11 and the water supplied through the further inlet port 18.

At its opposite end the mixing channel 11 is provided with an outlet port 28 for the ready made water gel, this outlet port being connected to an outlet tube 30 mounted at the upper end of the body 9 and running through the bore within the lock washer 6, the outlet port 28 being connected to the tube 30 via a channel 29. This output tube 30 could be designed with a suitable spraying mouthpiece for the water gel or as shown in FIG. 1 being designed for connection of a short hose for spraying the water gel.

As described above the water is forced to the gel mixer 8 through the tubes 17 and 26 from the water tank 1 by means of the pressure which is obtained within the tank 1 when the pressure gas container 4 is opened. As also mentioned above the liquid gel former shall be forced into the gel mixer 8 through the tube 15 by means of pressure. It is thus required that gas pressure is also obtained within the gel former container 5. This is achieved by connecting the upper part of the interior of the water tank 1 through an opening 31 within the tube 7 for the gel former container 5 and a corresponding channel 32 within the gel former container 5 to the space 33 between the lock washer and the upper surface of the body 9 so that the same gas pressure will appear within this space as within the interior of the tank 1. The space 33 is in turn connected to the interior of the gel former container 5 under the body 9 via an" inner channel 34 at the upper end of the body 9, an axial groove 35 within the envelop surface of the body 9 and a channel 36 at the bottom of the body 9. Through the connection 31, 32, 33, 34, 35, 36 pressure gas from the interior of the tank 1 will thus be supplied to the interior of the gelformer container 5 so that pressure is formed within the gel container which forces the liquid gel former through the tube 15 to the gel mixer 8. Within the channel 34 at the upper end of the body 9 a membrane 37 is provided which normally disconnects the channel 34 but is dimensioned in such a way that when opening the pressure gas container 4 it collapses by the pressure obtained in the space 33 and thus making it possible for the gas to flow from the interior of the water tank 1 to the interior of the gel former container. The purpose of the membrane 37 is to prevent gel former from flowing through the connection 36, 35, 34, 33, 32, 31 to the interior of the water tank in case the fire extinguisher when stored or handled should be turned upside down.

It will be realized that several embodiments of a gel mixer according to the invention will be possible. Thus the essential feature of the gel mixer according to the invention is that it comprises a long continuous flow and mixing channel which at its upstream end is provided with two inlet ports for water and gel former re-.

spectively and which along its extension is provided with a number of further inlet ports for water, the downstream end of the mixing channel being provided with an outlet port for the ready water gel. The constructive design of the gel mixer could however be varied to a high degree depending on the intended purpose of the mixer and the preferred manufacturing methods. It is however most suitable that the long continuous stream flow and mixing chamber runs according to a meandering course, a helical shape or some other suitable way so that it will occupy a reasonable space.

FIG. 10 shows schematically an example of a second embodiment of a gel mixer according to the invention which could also be used within the hand fire extinguisher shown in FIG. 1. The gel mixer shown in FIG. 10 also comprises a central cylindrical body 38 which is surrounded by a tubular socket 39 which in the drawing is somewhat axially displaced from the body 38. The body 38 is provided with a helical groove 38 in its envelop surface, this groove forming the long continuous flow and mixing chamber for the water gel. The groove 40 is provided with an inlet port 41 for the gel former and another inlet port 42 for. water. The gel former is supplied to the inlet port 41 via a schematically shown supply tube 43 and an internal channel within the body 38. The water inlet port 42 is supplied in a corresponding way via a'schematically shown water supply tube 44 and a channel within the body 38. The

flow and mixing channel 40 is further provided with a number of water inlet ports 45, 46, and 47 which are supplied with water through internal channels within the body 38 from the water supply tube 44 or another with a constriction 48 immediately after the water inlet port 45. At its downstream end the mixing channel 40 is provided with an outlet port 49 for the water gel, this port being connected to an outlet tube 50.

In FIG. 11 there is shown schematically a third possible embodiment of a gel mixer according to the invention which also could be used in the hand fire extinguisher shown in FIG. 1. This gel mixer is made by a number of flat discs 51, 52, 53, 54, 55, 56 which in the drawing are shown at a distance from each other but in reality are piled close to one another, and a surrounding socket 57 which in the drawing is shown axially displaced from the discs 5l-56. Each of the discs 51-55 is on one side provided with a meandering groove 58. These grooves in the piled discs 51-56 are connected to each other via an axial bore 59 in the discs 51-55 at the ends of the grooves 58 so that the different grooves form a continuous flow and mixing channel. At the upstream end of this channel within the disc 51 there is arranged an. inlet port 60 for the gel former and an inlet port 61 for water. Furthermore a number of further inlet ports 62 for water are arranged along the mixing channel in the discs 53-54. The gel former is supplied to the inlet port 60 via a schematically shown supply tube 63, whereas water is supplied to the inlet port 61 and 62 via a schematically shown supply tube 64 and a channel formed by a groove 65 in the outer surface of the discs 51-55. The ready made water gel is fed from the mixing chamber via a schematically shown outlet port 66 which is connected to the disc 56 which also serves as a cover for the mixer. It will be understood that this mixer according to the invention will function in essentially the same way as the previously described gel mixers. It is further understood that the grooves 58 within the piled discs 51-55 not necessarily have to have a zigzag shape but could instead run along a helical line or in some other suitable way.

Another modification which is very advantageous from the manufacturing point of view consists therein that each of the grooved discs 5155 is replaced by two adjacent discs, one of which is provided with a groove corresponding to the groove 58 whereas the other disc is provided with a through hole for the series connection of the mixing channel. By such a design it will be possible to manufacture all discs only using stamping technique.

Although the invention has been described above in connection with devices for the forming of water gel for fire fighting it will be understood that a gel mixer according to the invention also could be used for forming gels of other liquids than water and intended for other purposes than fire fighting. It is further understood that an apparatus according to the invention for the forming of water gel for fire fighting also could be used in other fire fighting instruments than hand fire extinguishers. Thus the apparatus according to the invention could eg be used within a sprinkler system where a gel mixer according to the invention could be mounted in immediate connection of every sprinkler mouthpiece.

We claim:

1. Apparatus for forming water gel, especially for fire fighting purposes, by continuous mixture of water and a liquid gel former, characterized in, that it comprises a mixing chamber provided interiorly with an elongated continuous flow and mixing channel, the upstream end thereof being provided with two inlet ports for water 7 and gel former respectively and along its length is provided at spaced intervals with a number of further inlet ports for water and the downstream end of said channel comprising an outlet for delivery of the ready made water gel, the total length of said channel exceeding the length of said chamber.

2. Apparatus according to claim 1, characterized in, that the mixing channel has a meandering shape whereby it occupies a small volume with respect to its total length.

3. Apparatus according to claim 1, characterized in, that the mixing channel is provided with a constriction arranged immediately upstream of the first and said further water inlet ports.

4. Apparatus according to claim 2, characterized in, that it comprises a cylindrical body the envelope surface of which is provided with a zigzag or helical groove which forms said fiow or mixing channel and which is surrounded by a cylindrical socket, the cylindrical body being provided with internal supply channels for water and gel former running from one end surface of the body to said inlet ports for gel former and water repsectively to the mixing channel.

5. Apparatus according to claim 4, characterized in, that the cylindrical body is provided with an internal outlet channel for the water gel running from the opposite end surface of the body to the downstream end of the mixing channel.

6. Apparatus according to claim 1, characterized in,

that it comprises a pile of several flat discs, several of the discs at different levels in the pile being provided with a meandering or helical groove and the discs at different levels in the pile being connected in series via axial through bores -in the discs so as to form the elongated continuous flowand mixing channel.

7. Apparatus according to claim 6, characterized in, that the discs are cylindrical and that the pile of discs is surrounded by a cylindrical socket.

8. Apparatus according to claim 7, characterized in, that the supply tubes for gel former and water respectively are connected to the disc at one end of the pile whereas an output port for water gel is connected to the opposite end disc.

9. Apparatus according to claim 1, characterized in, that said mixing channel is provided with first tube meansfor supplying water to the water inlet ports from a water container, and also is provided with second tube means for supplying gel former to the gel former inlet port from a gel former container, and means for supplying gas under pressure to said water container and said gel former container to force water and gel former from the respective containers through said first and second tube means to said mixing channel.

10. Apparatus according to claim 9, characterized in, that a first container for containing said supply of water, a second container for containing said supply of gel former, and a third container for containing said supply of gas under pressure, said second and third containers and said mixing channel being disposed within said first container, and valve means for controlling the supply of said gas.

11. Apparatus according to claim 10, wherein said valve means includes a membrane rupturable in response to release of gas under pressure from said third container to admit said gas to the interior of the second chamber.

12. Apparatus according to claim 11, wherein said said further inlet ports along the mixing channel. 

1. Apparatus for forming water gel, especially for fire fighting puprposes, by continuous mixture of water and a liquid gel former, characterized in, that it comprises a mixing chamber provided interiorly with an elongated continuous flow and mixing channel, the upstream end thereof being provided with two inlet ports for water and gel former respectively and along its length is provided at spaced intervals with a number of further inlet ports for water and the downstream end of said channel comprising an outlet for delivery of the ready made water gel, the total length of said channel exceeding the length of said chamber.
 2. Apparatus according to claim 1, characterized in, that the mixing channel has a meandering shape whereby it occupies a small volume with respect to its total length.
 3. Apparatus according to claim 1, characterized in, that the mixing channel is provided with a constriction arranged immediately upstream of the first and said further water inlet ports.
 4. Apparatus according to claim 2, characterized in, that it comprises a cylindrical body the envelope surface of which is provided with a zigzag or helical groove which forms said flow or mixing channel and which is surrounded by a cylindrical socket, the cylindrical body being provided with internal supply channels for water and gel former running from one end surface of the body to said inlet ports for gel former and water repsectively to the mixing channel.
 5. Apparatus acCording to claim 4, characterized in, that the cylindrical body is provided with an internal outlet channel for the water gel running from the opposite end surface of the body to the downstream end of the mixing channel.
 6. Apparatus according to claim 1, characterized in, that it comprises a pile of several flat discs, several of the discs at different levels in the pile being provided with a meandering or helical groove and the discs at different levels in the pile being connected in series via axial through bores in the discs so as to form the elongated continuous flow- and mixing channel.
 7. Apparatus according to claim 6, characterized in, that the discs are cylindrical and that the pile of discs is surrounded by a cylindrical socket.
 8. Apparatus according to claim 7, characterized in, that the supply tubes for gel former and water respectively are connected to the disc at one end of the pile whereas an output port for water gel is connected to the opposite end disc.
 9. Apparatus according to claim 1, characterized in, that said mixing channel is provided with first tube means for supplying water to the water inlet ports from a water container, and also is provided with second tube means for supplying gel former to the gel former inlet port from a gel former container, and means for supplying gas under pressure to said water container and said gel former container to force water and gel former from the respective containers through said first and second tube means to said mixing channel.
 10. Apparatus according to claim 9, characterized in, that a first container for containing said supply of water, a second container for containing said supply of gel former, and a third container for containing said supply of gas under pressure, said second and third containers and said mixing channel being disposed within said first container, and valve means for controlling the supply of said gas.
 11. Apparatus according to claim 10, wherein said valve means includes a membrane rupturable in response to release of gas under pressure from said third container to admit said gas to the interior of the second chamber.
 12. Apparatus according to claim 11, wherein said first tube means includes one water supply tube communicating with the upstream end of the mixing channel and another water supply tube communicating with said further inlet ports along the mixing channel. 